The present study investigated the possibility of heritage language loss in twenty students of Hispanic origin, selected from six second-grade classrooms in one elementary school of a large district in the Dallas-Fort Worth area. Ten students were enrolled in Transitional Bilingual Education (TBE) classes and ten students were enrolled in English as a Second Language (ESL) classes, during the academic year 2004-2005. Oral Reading Fluency (ORF) in English and Spanish were measured over a short-term progress monitoring period (i.e. sixteen consecutive weeks), and over a long-term follow-up period (i.e. nine and twelve months later, respectively). To answer the first research question on the amount and type of growth in English and Spanish ORF demonstrated by the students over time, two main types of analyses were conducted: a) time series analysis of group improvement trends, and b) Analysis of Variance (ANOVA) on individual student slope coefficients. Results from quantitative analyses revealed that both groups of students improved in English reading over time. However, when considering the long-term progress, the TBE group demonstrated a faster rate of improvement in English reading when compared to the ESL group and also to their own Spanish reading. As for the ESL group, the students reached a plateau of performance in Spanish, indicating, at best, minimal skills in the heritage language while continuing to progress in English. To answer the second research question, regarding parents’ beliefs on bilingualism and maintenance of the heritage language in their children, semistructured Parents’ Interviews (PI) with open-ended questions were conducted. Results from qualitative analyses revealed three major themes: Both sets of parents believed in the connection between the native language and increased life opportunities, the TBE parents affirmed the heritage language as symbol of their cultural identity, and the ESL parents acknowledged their children’s native language loss. Findings from this study suggest that students instructed in their native language in the early elementary years appear to have a better chance of maintaining their heritage language over time, when compared to students instructed solely in English.